Application of Arrhenius Equation to Predict the Self Life of Food Commodities
Description shelf life (expiry date) of food products represents one of the information required to be specified by the manufacturer on the label of food packaging. The inclusion of information on the shelf life li fe become very important, as it related to food safety and product quality assurance at the time the product arrived to consumer. The obligation about shelf life on food labels is set in the food laws number 7/1996 and government regulations number 69/1999 about label and food advertisement. Food product shelf life is the time interval between production time until consumption in which products are in satisfactory condition on the nature of appearance, taste, texture and aroma of a good nutritional value. A product is said to be in the range where the quality of life of the product is acceptable in general for purposes as desired desi red by the consumer and for packaging material mater ial still sti ll has the integrity and protect packaging. packaging. Information about the product shelf shelf life is very very important for consumers, producers, sellers and distributors. Consumers will know the level of safety and feasibility of the product to be consumed in addition to know the indications of the change in taste, appearance or nutritional content. For producers, this information is part of the marketing concept and very important for the use of packaging materials used. used. And for sellers and distributors, product shelf life’s information is important for stock handling product. One way to determine the shelf-life of food products can be done by storage product in storage conditions and measure the actual time savings products. This will give us the most accurate estimates of time, but requires a lot of time and great cost. Difficulties often faced by industry in determining the shelf life is time, because for producers this can inhibit the release of the product. Therefore we need ways to predict product shelf life fast, cheap, easy and close to the actual shelf life. One way that can be used is Arrhenius equation. Arrhenius equation is widely used to predict the shelf life of products where the product is easily damaged due to chemical reactions such as lipid oxidation, Maillard reaction, and protein denaturation. Shelf life of food products is usually determined by using this equation is the food cans, milk UHT, powdered milk or formula milk, snacks, fruit juices,
instant noodles, frozen meat and food products containing high fat or sugar reduces or protein.
Because the chemical reaction in general is influenced by temperature, the Arrhenius model simulates the acceleration of product defects on the storage conditions of high temperature above normal storage temperature. The rates of chemical reactions that can lead to damage to food products generally follow the order of reaction 0 or 1. Which include reaction order 0 are enzymatic degradation, such as fresh fruits and vegetables, frozen foods product, non-enzymatic browning, such as dry seeds, dry milk products and reduced nutritional value protein, and oxidation of fats, such as increasing rancidity on snacks, dry foods and frozen products. While the damage of food included in the reaction order 1 are rancidity in salad oil, and dried vegetables, growth of microorganisms in meat and fish and microorganisms death because heat treatment, off flavor production by microbes, destruction of vitamins in canned food and dry food, loss of protein quality of dry food. In reaction order 0, rate of change expressed as follows:
dA
dt
k z ,
with integrating both sides obtained: A=A 0=k zt or Ae=A0-k zts
In the reaction order 1, the percentage loss per-day shelf life is constant at constant temperature. The first reaction order, with a decrease exponentially so rate of change expressed as follows:
dA
dt
with
k f A,
with integrating obtained: ln A=ln A 0-K ft or ln Ae=ln A0-K ft s
A0
= value of initial quality
A
= the quality of the remaining value later
Ae
= the value of A in end of shelf life
ts
= shelf life, in days, months, years, etc.
K f
= reaction constant in reaction order 1
Arrhenius equation used on several assumptions, among others, changes in the quality factor is determined only by one reaction, no other factors that cause changes in quality, and temperature during storage is considered constant. Therefore there will be conditions which will result in the diversion.
1. With increasing temperature phase change can happen, for example, solid fats to liquid fats. Reactants are not anymore in the solid phase. Because of that shelf life at lower temperatures result is lower than the true value. 2. Water binding occurs in the dry product, depending on temperature, this will result in higher water activity with increasing temperature at constant water content. Increasing in water activity will increase the reaction rate constant value. 3. If the product is not stored on impermeable bags or containers total, storage products at high temperature in the drying cabinet will accelerate the loss of water content. This will lead to the degradation rate is lower than the level of permanent
